Iterative dynamic condensation method of finite element model for rotor-bearing system

For structures with damping and gyroscopic effects, an iterative dynamic condensation method of finite element model is proposed in this paper, which is able to simultaneously reduce the mass, damping, gyroscopic and stiffness matrices of the rotor-bearing system. The numerical example of a simple rotor-bearing system is used to verify the present method. The critical speed and steady-state displacement response of the rotor-bearing system are calculated and compared using the proposed reduced model and full model, and the results show that the reduced model can accurately calculate the critical speed. When the speed is lower than the second-order critical speed, the reducd model proposed in this paper can accurately predict the steady-state response of the rotor system(except for the critical speed), and it can be used for the unbalance fault diagnosis of the rotor-bearing system.